US Secretary of State wraps up GCC trip after traveling to Doha for the second time in 48 hours.

US Secretary of State Rex Tillerson has wrapped up a four-day mission in the Gulf with little sign of progress on ending the GCC crisis.

Tillerson met Qatar's Emir Sheikh Tamim bin Hamad Al Thani for the second time in 48 hours, together with a Kuwaiti mediator, on the final leg of his trip trying to repair a rift that is dividing some of America's most important Middle East allies, before heading back to Washington on Thursday.

Despite an intense round of shuttle diplomacy that also took him to Kuwait and Saudi Arabia, tensions remain high between Qatar and four Arab states that accuse Doha of funding "terrorism" and is being too close to Iran - allegation Qatar has repeatedly denied.

Tillerson's clearest achievement has been to secure a memorandum of understanding with Qatar to strengthen its counterterrorism efforts.

"Since Qatar signed the memorandum of understanding with US, newspapers owned by Saudi Arabia and the UAE lashed out at Tillerson, blaming him to be leaning towards Qatar and describing the shuttle diplomacy as something that is not going to come up with any tangible results," he said.

French Foreign Minister Jean-Yves Le Drian is expected to arrive in the region over the next few days.

Saudi Arabia, the United Arab Emirates, Bahrain and Egypt imposed a land, sea and air blockade on Qatar since June 5.

The anti-Doha quartet is holding fast to its insistence that Qatar bow to a 13-point list of demands that includes shutting down Qatar's Al Jazeera Media Network, sever all alleged ties with the Muslim Brotherhood and with other groups, including Hezbollah, al-Qaeda and ISIL(also known as ISIS), limiting Qatar's ties with Iran and expelling Turkish troops stationed in country.

Qatar denies the charges of extremism and called the demands "unrealistic".

On Thursday, a human-rights group said abuses were caused by the Saudi-led group's blockade.

"Hundreds of Saudis, Bahrainis, and Emiratis have been forced into the impossible situation of either disregarding their countries' orders or leaving behind their families and job," said Sarah Leah Whitson of Human Rights Watch.

The US and its Western allies have vast economic and political interests in the Gulf, which pumps one fifth of the world's oil supplies.